Workaround for built-in shaders on some ES2 devices which don't support highp in pixel shaders.

src/modules/graphics/Shader.cpp

@@ -89,7 +89,12 @@ static const char render_uniforms[] = R"(
 // According to the GLSL ES 1.0 spec, uniform precision must match between stages,
 // but we can't guarantee that highp is always supported in fragment shaders...
 // We *really* don't want to use mediump for these in vertex shaders though.
+#ifdef LOVE_SPLIT_UNIFORMS_PER_DRAW
+uniform LOVE_HIGHP_OR_MEDIUMP vec4 love_UniformsPerDraw[12];
+uniform LOVE_HIGHP_OR_MEDIUMP vec4 love_UniformsPerDraw2[1];
+#else
 uniform LOVE_HIGHP_OR_MEDIUMP vec4 love_UniformsPerDraw[13];
+#endif
 
 // Older GLSL doesn't support preprocessor line continuations...
 #define TransformMatrix mat4(love_UniformsPerDraw[0], love_UniformsPerDraw[1], love_UniformsPerDraw[2], love_UniformsPerDraw[3])
@@ -100,8 +105,13 @@ uniform LOVE_HIGHP_OR_MEDIUMP vec4 love_UniformsPerDraw[13];
 
 #define CurrentDPIScale (love_UniformsPerDraw[8].w)
 #define ConstantPointSize (love_UniformsPerDraw[9].w)
-#define ConstantColor (love_UniformsPerDraw[12])
-#define love_ScreenSize (love_UniformsPerDraw[11])
+#define ConstantColor (love_UniformsPerDraw[11])
+
+#ifdef LOVE_SPLIT_UNIFORMS_PER_DRAW
+#define love_ScreenSize (love_UniformsPerDraw2[0])
+#else
+#define love_ScreenSize (love_UniformsPerDraw[12])
+#endif
 
 // Alternate names
 #define ViewSpaceFromLocal TransformMatrix
@@ -538,6 +548,11 @@ std::string Shader::createShaderStageCode(Graphics *gfx, ShaderStageType stage,
 	if (info.usesMRT)
 		ss << "#define LOVE_MULTI_RENDER_TARGETS 1\n";
 
+	// Note: backends are expected to handle this situation if highp is ever
+	// conditional in that backend.
+	if (!gfx->getCapabilities().features[Graphics::FEATURE_PIXEL_SHADER_HIGHP])
+		ss << "#define LOVE_SPLIT_UNIFORMS_PER_DRAW 1";
+
 	for (const auto &def : options.defines)
 		ss << "#define " + def.first + " " + def.second + "\n";
 
@@ -1164,11 +1179,12 @@ static StringMap<Shader::Language, Shader::LANGUAGE_MAX_ENUM> languages(language
 
 static StringMap<Shader::BuiltinUniform, Shader::BUILTIN_MAX_ENUM>::Entry builtinNameEntries[] =
 {
-	{ "MainTex",              Shader::BUILTIN_TEXTURE_MAIN      },
-	{ "love_VideoYChannel",   Shader::BUILTIN_TEXTURE_VIDEO_Y   },
-	{ "love_VideoCbChannel",  Shader::BUILTIN_TEXTURE_VIDEO_CB  },
-	{ "love_VideoCrChannel",  Shader::BUILTIN_TEXTURE_VIDEO_CR  },
-	{ "love_UniformsPerDraw", Shader::BUILTIN_UNIFORMS_PER_DRAW },
+	{ "MainTex",               Shader::BUILTIN_TEXTURE_MAIN        },
+	{ "love_VideoYChannel",    Shader::BUILTIN_TEXTURE_VIDEO_Y     },
+	{ "love_VideoCbChannel",   Shader::BUILTIN_TEXTURE_VIDEO_CB    },
+	{ "love_VideoCrChannel",   Shader::BUILTIN_TEXTURE_VIDEO_CR    },
+	{ "love_UniformsPerDraw",  Shader::BUILTIN_UNIFORMS_PER_DRAW   },
+	{ "love_UniformsPerDraw2", Shader::BUILTIN_UNIFORMS_PER_DRAW_2 },
 };
 
 static StringMap<Shader::BuiltinUniform, Shader::BUILTIN_MAX_ENUM> builtinNames(builtinNameEntries, sizeof(builtinNameEntries));